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Headers or ?

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wayne

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Well after pulling the K5 apart for the engine swap I need to figure out what to do about the exhaust. I have one cracked manifold that needs replaced, the other is not cracked but has the ususal manifold shrinking problem. Also my Y pipe is pretty wasted from hitting to many rocks on the bottom and the drive shaft making room to flex on the top. Oh, and the tailpipe, well I replaced that for inspection last summer and that didn't last a week and the rocks kinda took their toll. I am pretty sure the easy answer is to do dual exhaust so I don't have to worry about the Y pipe, tuck them in and relocate the rear shocks and run the tailpipes out the side behind the rear tires. My decision is what headers to go with. I don't want long tube headers that hang down low and get in the way so I am thinking about short headers or just getting a new manifold and comming off them. Anyway, what headers work well without getting in the way? This is a stock TBI 350 and will have no cats on it.
 
blazin_blazer said:
ramhorn manifolds.....chevy engineered the motor w/cast exhaust for a reason
Click to expand...

GM engineered the motor for fuel economy and also emissions and also the cast manifolds are cheaper to produce. The best thing ever would be to replace the stock manifolds with a header for better performance and allow the engine to breathe alot easier.
 
4X4HIGH said:
GM engineered the motor for fuel economy and also emissions and also the cast manifolds are cheaper to produce. The best thing ever would be to replace the stock manifolds with a header for better performance and allow the engine to breathe alot easier.
Click to expand...

Are smog legal headers worth it? My stock ones have the cold air injectors... I have read somewhere that buying/installing aftermarket headers isn't worth due to the smog crap.
 
kablooie said:
Are smog legal headers worth it? My stock ones have the cold air injectors... I have read somewhere that buying/installing aftermarket headers isn't worth due to the smog crap.
Click to expand...

I'm not running any smog stuff.:D
 
Take a look at other manufacturers, Heep for one, many use much more of a tubular header design than a cast design, for a reason...

#1 torque/hp mod to a powerplant.

if you want to keep them tucked up, I'd be looking at Thorleys or Hedman Elites.. Shorty's are pretty useless performance-wise...
 
good luck with the visual in pa.it wont pass without cats.unless this is going to be a purely offroad vehicle.i have standard full length headers.our trucks are tall enough that the longer ones are not really a issue.mine sit right at the framerail or maybe just slightly below.they are protected by the engine so no worries there.you can also run strait pipes down the frame from the collector instead of trying to make extra bends to the exhaust.
wayne said:
I'm not running any smog stuff.:D
Click to expand...
 
chulisohombre said:
good luck with the visual in pa.it wont pass without cats.unless this is going to be a purely offroad vehicle.i have standard full length headers.our trucks are tall enough that the longer ones are not really a issue.mine sit right at the framerail or maybe just slightly below.they are protected by the engine so no worries there.you can also run strait pipes down the frame from the collector instead of trying to make extra bends to the exhaust.
Click to expand...

My K5 is exempt from emissions. I am going to double check today though to see what the scoop is. I have been told that if you are exempt (less then 5000 miles a year) then you can get rid of all the smog stuff. In all reality, the 89 to 91 K5's really only have a cat for emissions. They did not have a smog pump from the factory.
 
Let it BREATHE...

Headers all the way... I have the Hedmans on the buggy, no clearance issues. Only one suggestion, Pony up for the nice copper gaskets at the collector flange and double nut them. The paper gaskets blow out too easily IMO. I like copper gaskets at the mating sufface too. Plus they are reusable:waytogo:
 
the cast manifolds keep the exhaust gases hotter, therefor flowing faster. no doubt not as free as headers, but other things to add to equation:

when gm designed the rams horns...emissions wasn't really much of a factor.

also the/any cast manifold, helps keep under hood temps down...motor using cooler air makes more power....i think the ram horn is 1 of the best flowing stock manifolds...i know mine are, i had them extrude honed
 
The exhaust is colliding in any log style manifold, which is counter to what you want. Besides you are forcing it to change direction more than in a header. Obviously some manifold designs are better than others, and headers are the same way. Look at newer manifolds, especially the LS1 stuff, and you'll see how poor even prior manifolds were.

If the OP ponies up for hedman elites, they come with the ball/socket flanges, you will never have to worry about collector gasket leaks. One less gasket than even manifolds.

Getting internally coated headers can also help power production, while vastly reducing underhood heat.
 
http://www.pacode.com/secure/data/067/chapter177/chap177toc.html

Wayne, its not as simple as being exempt. technically you still have to have all the equipment hooked up to pass a visual inspection. they might not check the actual output because of mileage but you need to find the right shop. a lot of shops will not write an exempt sticker unless they wrote the sticker that they are now replacing. you can fight them on it but who wants to piss off the guy that decides if you get an inspection.

not trying to be a downer, just slow you down some before you tear off all the emmisions.


http://coloradok5.com/forums/showthread.php?t=198998&highlight=header

if you got the coated ones I think they would do what you want.
 
I have long tube headers (Flowtech) and would probably be better off with stock manifolds.

Sure, headers make more power but they leak (unless you spend big $$$) and long tube headers generally interfere with both the front driveshaft and the shackle. I've hit rocks on the headers on two or three occasions too.

ryoken said:
Take a look at other manufacturers, Heep for one, many use much more of a tubular header design than a cast design, for a reason...

#1 torque/hp mod to a powerplant.
Click to expand...

Heads are much more relevant to hp/torque as is the intake/cam profile. Exhaust/intake make some difference but not a huge amount IMO.

I think that the OEM's use cast manifolds because they are cheap to produce and are less prone to leaks/cracking (i.e. reliability at the sacrifice of a tiny bit of power).

For the record my family had an '88 Olds station wagon (3.3L V6) that basically had shorty headers in place of cast manifolds (stock)




I don't understand why anyone gets riled up about the ramhorn manifolds, they aren't as good as headers and probably don't even flow as well as more modern manifolds, likely the reason racers liked them is because they were limited to stock manifolds (and the ramhorns were the best back in the day).
 
Even on a moderate 350, good headers are worth 40HP. That's a hell of a lot of power for a $200 investment.
 
gmc4cw said:
http://www.pacode.com/secure/data/067/chapter177/chap177toc.html

Wayne, its not as simple as being exempt. technically you still have to have all the equipment hooked up to pass a visual inspection. they might not check the actual output because of mileage but you need to find the right shop. a lot of shops will not write an exempt sticker unless they wrote the sticker that they are now replacing. you can fight them on it but who wants to piss off the guy that decides if you get an inspection.

not trying to be a downer, just slow you down some before you tear off all the emmisions.


http://coloradok5.com/forums/showthread.php?t=198998&highlight=header

if you got the coated ones I think they would do what you want.
Click to expand...

I checked into the deal today about being exempt to make sure and as long as it is exempt and does not exceed 5000 miles a year you can get rid of all the smog stuff. The place that does my inspections http://www.morethantires.com/HomePage.html looked it up today for me.
 
IMO the best shortys out there is the Edelbrock TES system. Stainless steel headers. Custom high flow Y pipe to single 3". It will even bolt right up to stock exhaust.
I have had mine on my k5 for 9 years absoulity no rust on the headers. No leaks. I have Never replaced any gaskets.
50 state legal.
Builds good torque. Real good throttle responce.
I like single 3"exhaust way better than dual. Less pipe, muffs, ect to get banged up and torn off on the rocks.
TBI likes single 3" too.
 
Thunder said:
IMO the best shortys out there is the Edelbrock TES system. Stainless steel headers. Custom high flow Y pipe to single 3". It will even bolt right up to stock exhaust.
I have had mine on my k5 for 9 years absoulity no rust on the headers. No leaks. I have Never replaced any gaskets.
50 state legal.
Builds good torque. Real good throttle responce.
I like single 3"exhaust way better than dual. Less pipe, muffs, ect to get banged up and torn off on the rocks.
TBI likes single 3" too.
Click to expand...

I thought that way too about a single 3". I was running a Flowmaster cat back and a Catco high flow converter. The y pipe looks like it is a rock slider and the Flowmaster tailpipe didn't like rocks either. I replaced the tailpipe and it lasted 4 days untill rocks bit it. The new exhaust will get tucked up and should be pretty safe from rocks. Another problem is the Y pipe and the front driveshaft like each other. I could have a custom Y Pipe made but after looking at it for about 30 minutes, there is no place I want to run the crossover pipe that will work good. I am not doing this for the extra hp, I'm simply curing a problem. I am also planning for a set of Hedman glasspack mufflers because they are small, short, and easy to tuck up underneith.
 
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